You can use Navidrome to stream your music files (flac, mp3, etc.), and make it accessible to your network or on the internet.
It is opensource and runs on Windows, Linux, and MacOS. Your digitial files need to be tagged though e.g. Artist, Album, etc.
You can play the music via a web browser e.g. http://localhost:4533, or alternatively you can use one of the compatible Android or IOS Clients.
Anyone with access to the server can then also play your music independently on their own devices.
I have been using it for a while, and it is easy to setup and use.
There is a demo link on the github page.
[To add addtional solutions from comments]
If you don't want to host, you can upload the music files to say a service like MixCloud, after creating an account. You can then play directly via webrowser (laptop/computer or mobile phone) or via their mobile phone app. It allows you to create playlists of material available or uploaded to the site.
Another similar solution is iBroadcast.